Evaporation characterization of fuel spray impinging on a flat wall by laser-based measurement

Abstract

It is of interest for engine combustion modeling to quantify the evaporation behaviors of fuel spray impinging on a wall as the fuel atomization, evaporation, and mixing with oxygen in the combustion chamber usually dominate the subsequent combustion processes. In this study, the vapor and liquid mass distributions in diesel-like fuel sprays were quantified using the ultraviolet-visible laser absorption scattering imaging technique. The sprays were injected from a single-hole nozzle with a common-rail injection system and impinged on a flat wall at an ambient pressure of 4 MPa and an ambient temperature of 833 K. The mass of the total fuel vapor, the spray volume covered by the vapor phase, and the air mass entrained into the spray were characterized. The results indicate that the time evolution of these parameters until shortly after the end of injection can be expressed by a power-law function, Yi = ki· ts1.5, where Yi represents the parameter like vapor mass and so on, ts is the time after start of injection, and ki is the coefficient corresponding to Yi. The physics behind this power-law function was analyzed and discussed based on the theory of atomization and evaporation, and verified using measurement data obtained under different conditions of injection quantity.